This invention relates to a sanitary napkin absorption and containment of menstrual discharge.
Japanese Utility Model Application Disclosure Gazette (Kokai) No. Hei7-33315 discloses a sanitary napkin consisting of upper and lower napkins each comprising a liquid-absorbent core covered with a liquid-pervious sheet. The upper napkin having a longitudinal dimension smaller than that of the lower napkin lies on a middle region of the lower napkin. A pair of elastic members extend longitudinally along transversely opposite side edges of the upper napkin beyond longitudinally opposite ends of the upper napkin and are fixed under tension to longitudinally opposite ends of the lower napkin at respective ends of these elastic members. The upper and lower napkins can relatively move without being restricted by each other within a considerably wide range.
In the known sanitary napkin, a lower surface of the upper napkin normally remains in contact with the upper surface of the lower napkin and operate as if these two napkins are assembled in a single napkin. Specifically, the liquid-pervious sheet covering the upper napkin is placed upon the liquid-pervious sheet covering the lower napkin. Such situation may obstruct a rapid transfer of menstrual discharge from the upper napkin to the lower napkin. In consequence, there is apprehension that a portion of menstrual discharge might leak sideways before it transfers to the lower napkin especially when a large quantity of menstrual discharge is discharged.
It is an object of this invention to provide a sanitary napkin including upper and lower liquid-absorbent cores in which so that menstrual discharge can rapidly transfer from the upper absorbent core to the lower absorbent core and thereby any apprehensive leakage of menstrual discharge can be avoided.
According to the present invention, there is provided a sanitary napkin including a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between the topsheet and the backsheet, the sanitary napkin being contoured by a pair of opposite side edges extending longitudinally of the napkin and a pair of opposite ends extending between the pair of opposite side edges, wherein: the topsheet is dimensioned to have a width larger than that of the backsheet and transversely opposite sides of the topsheet is folded back inwardly of the napkin along a pair of folding lines extending longitudinally of the napkin and the folded portions are further folded outwardly of the napkin so as to form a pair of pleats and extend from the pleats to the respective side edges of the napkin along which the topsheet is bonded to the backsheet; the absorbent core includes a lower absorbent core and an upper absorbent core, the lower absorbent core is placed on an inner surface of the backsheet and extends between the opposite side edges and between longitudinally opposite ends of the napkin; the upper absorbent core is dimensioned to be shorter than the lower absorbent core and separably placed upon an inner surface of the lower absorbent core; the upper absorbent core is bonded to an inner surface of the topsheet so that the upper absorbent core is spaced from the opposite ends of the napkin and the pleats lie between the transversely opposite side edges of the lower absorbent core and the transversely opposite side edges of the upper absorbent core; and at least portions of said topsheet are provided along the opposite side edges of the upper absorbent core with elasticity being effective longitudinally of the napkin.
According to one embodiment of this invention, the upper absorbent core lies to one of the longitudinally opposite ends of the napkin.
According to another embodiment of this invention, the elasticity of the topsheet is given by elastic members in the form of threads, ribbons or sheets.
According to still another embodiment of this invention, the elasticity of the topsheet is given by an elastic sheet used as the topsheet being bonded under tension in the longitudinal direction.
According to a further embodiment of this invention, the maximum dimension by which the upper absorbent core is spaced from the lower absorbent core in response to contraction of the topsheet is in a range of 5xcx9c50 mm.
According to an additional embodiment of this invention, a plurality of said pleats are formed on both sides of the upper absorbent core, respectively.